In a hospital environment, sterilization is generally accomplished by one of three methods: 1) exposure to a sterilant gas; 2) steam autoclaving; or 3) immersion into a liquid sterilant. Because of the inability of some endoscope materials to withstand autoclaving temperatures, and because gas sterilization may be unavailable or impractical in some situations, it is desirable for an endoscope to be sterilizable by liquid immersion.
Unfortunately, prior art adjustable-focus endoscopes such as those shown in copending application Ser. No. 720,590 filed Apr. 8, 1985 and entitled "Disposable Small Diameter Rigid Endoscope" could not be liquid-sterilized because the liquid would seep into the lens cavity of the eyepiece through the adjustment mechanism and would become trapped therein. It was therefore desirable to create an immersible or soakable endoscope which was easy to adjust, as inexpensive as possible to manufacture, and capable of maintaining its adjustment under rough handling.